Penalties for hand loss?

[Armorlord]

I know I've seen specific penalties for missing a hand before, but darned if I can remember where is which book.
Any pointers toward the right information?

In lieu of official rulings, I'm thinking -20% on skills requiring fine manipulation normally using two hands, or just taking twice as long if it doesn't need to be done in a hurry.

[Jorel]

You start to become more and more machine, eventually you are Darth Vader.

[dragonfett]

LOL